Thursday, October 26, 2006

False Optimism

MSNBC reported in May:

The 2006 Atlantic hurricane season will be very active with up to 10 hurricanes, although not as busy as record-breaking 2005, when Hurricane Katrina and several other monster storms slammed into the United States, the U.S. government’s top climate agency said on Monday.
“NOAA is predicting 13 to 16 named storms, with eight to 10 becoming hurricanes, of which four to six could become ‘major’ hurricanes of Category 3 strength or higher,” said Conrad Lautenbacher, administrator of the National Oceanic and Atmospheric Administration.


But unfortunately for him this never happened:

Instead, it has been a long, lazy hurricane season with just half the number of hurricanes predicted and not a single one making landfall.
"Weather forecasting is a chancy business,” said Hugh Willoughby, a professor of hurricane science at Florida International University. “It’s gotten a lot better, but if you can’t stand being wrong, you shouldn’t be in the business."


Thanks to Tim Blair who reports that

Can’t predict tomorrow’s weather, can’t predict next year’s weather ... yet there’s a scientific consensus about weather in the coming century and beyond. Just as well these folks are adapting to being wrong.


And what about Australian Hurricanes/Cyclones?



This graph on the left as given out by the ABM shows the number and intensity of cyclones from the year 1970 to 1998. They report

that the total number of cyclones has decreased in recent decades. However, the number of stronger cyclones (minimum central pressure less than 970 hPa) appears to have increased slightly.

Interesting. I don’t come to the same conclusion. My statistical analysis of the data given on that graph actually come to the conclusion of a statistically significant decrease in the number of cyclones over the period from 1970 to 1998. (F = 4.99, p = 0.034). For those not in the statistical know-how. Generally scientists prove a significant result if the p value is below 0.05 (5%). This means that there is a 3.4% chance that the decrease in cyclones in this period is due to luck or random variation.

My analysis of stronger cyclones proves no significant increase or decrease over this time period (F = 1.17, p = 0.289). Hence we can conclude, contrary to what was written by the ABM that there is no evidence to prove that strong cyclones have increased or decreased in the past 30 years, and strong evidence that the total number of cycles has significantly decreased.

I guess people see different things in graphs when they want to believe. Lucky we can test this to prove it instead.

2 comments:

hswiseman said...

Jonathan, any chance that you can get any of these seminar materials, particularly Wegman, which is rumored to be quite critical of the paleoclimate folks?


The following are the session descriptions from the ASA’s Joint Statistical Meeting held in August. Climate analysis is obviously a big deal to a number of these statisticians. There is no excuse for their absence in the analytic process.

Ah, to have been a fly on the wall…….

354 CC-400
Late-Breaking Session #2: What Is the Role of
Statistics in Public Policy Debates about Climate
Change?—Other
The ASA, ENAR, IMS, SSC, WNAR
Organizer(s): Edward Wegman, George Mason University; Richard L.
Smith, h e University of North Carolina at Chapel Hill
Chair(s): Douglas W. Nychka, National Center for Atmospheric Research
8:40 a.m. The Kyoto Accord, the 2001 IPCC Third
Assessment Report, and the Academic Papers
Underpinning Them—Edward Wegman,
George Mason University
9:05 a.m. National Research Council Report on the ‘Hockey
Stick Controversy’—J. Michael Wallace,
University of Washington
9:30 a.m. The CCSP Report on Temperature Trends in the
Lower Atmosphere—Richard L. Smith, h e
University of North Carolina at Chapel Hill
9:55 a.m. Floor Discussion

ALSO OF INTEREST

3:05 p.m. On Nonparametric Smoothing Methods
for Assessing Climate Change—Patricia
Menendez Galvan, Swiss Federal Research
Institute WSL/ETHZ; Sucharita Ghosh, Swiss
Federal Research Institute WSL

9:25 a.m. Statistical and Computational Issues in
Climate Research—Invited
Section on Statistical Computing, Section on Physical and Engineering
Sciences, Section on Statistical Graphics
Organizer(s): Donald B. Percival, University of Washington
Chair(s): Donald B. Percival, University of Washington
8:35 a.m. Statistical Analysis of Spatial Patterns of Climate
Variability—J. Michael Wallace, University of
Washington
9:00 a.m. Interpreting Recent Climate Change—Francis
W. Zwiers, Canadian Centre for Climate
Modelling and Analysis
9:25 a.m. Statistical Problems in Climate Change
and Geophysical Fluids—Carl Wunsch,
Massachusetts Institute of Technology
9:50 a.m. Disc: Richard L. Smith, h e University of North
Carolina at Chapel Hill
10:10 a.m. Floor Discussion

179 CC-613
Statistical Methods in Climate Modeling
and Seismology—Invited
WNAR, Section on Physical and Engineering Sciences, Section on Bayesian
Statistical Science, Section on Statistics and the Environment
Organizer(s): Gabriel Huerta, University of New Mexico
Chair(s): Gabriel Huerta, University of New Mexico
2:05 p.m. Probabilistic Projections of Climate Change:
Bayesian Models for Analyzing Ensembles of
Global Climate Models—
Claudia Tebaldi,
National Center for Atmospheric Research;
Richard L. Smith, h e University of North
Carolina at Chapel Hill; Douglas W. Nychka,
National Center for Atmospheric Research;
Linda O. Mearns, National Center for
Atmospheric Research
2:35 p.m. Uncertainty Estimation in Geophysics—?Mrinal
K. Sen, h e University of Texas at Austin
3:05 p.m. Estimating Parametric Uncertainties of the
Community Atmospheric Model (CAM3) and
Processes Controlling Global Climate Change—
Charles S. Jackson, h e University of Texas at
Austin
3:35 p.m. Floor Discussion

235 CC-214
Climate, Weather, and Spatial-Temporal
Models—Topic-Contributed
Section on Statistics and the Environment, Section on Statisticians in Defense
and National Security, Section on Bayesian Statistical Science, WNAR
Organizer(s): Stephan Sain, University of Colorado at Denver and
Health Sciences Center
Chair(s): Douglas W. Nychka, National Center for Atmospheric Research
8:35 a.m. Models for Multivariate Spatial Lattice Data
and Assessing Climate Change—
?Stephan Sain,
University of Colorado at Denver and Health
Sciences Center
8:55 a.m. Spatial Patterns of Global Climate Change
Fields—?Reinhard Furrer, Colorado School
of Mines; Reto Knutti, National Center for
Atmospheric Research
9:15 a.m. Modeling Precipitation Network Data When
Station Reporting Times Are Misaligned—
Jarrett Barber, Montana State University;
Alan E. Gelfand, Duke University; Douglas
W. Nychka, National Center for Atmospheric
Research
9:35 a.m. Spatial and Temporal Models for Evaluating IPCC
?Mikyoung Jun, Texas
Climate Model Outputs—
A&M University; Douglas W. Nychka, National
Center for Atmospheric Research; Reto Knutti,
National Center for Atmospheric Research
9:55 a.m. A Hierarchical Bayesian Spatio-Temporal Model
for Tropospheric Carbon Monoxide—?Anders
Malmberg, National Center for Atmospheric
Research
10:15 a.m. Floor Discussion

THERE ARE MORE, here is the link!

http://www.amstat.org/meetings/jsm/2006/PDFs/ProgramBook_Full.pdf

Jonathan Lowe said...

Wasn't there, but you can buy the proceedings here:
http://www.amstat.org/ASAStore/Books_CD-ROMs_C4.cfm